DCC
Short for Direct Cable Connection, a Windows 95 feature that enables two computers to be connected via a serial or parallel cable. Once connected, the two computers function as if they were on a local-area network (LAN). Either computer can access files on the other computer. But because DCC does not require network interface cards (NICs), it is less expensive and simpler. The limitations are that it can connect only two PCs, and the data transfer rate is slower than with a true LAN.

De facto Standard
A format, language, or protocol that has become a standard not because it has been approved by a standards organization but because it is widely used and recognized by the industry as being standard. Some examples of de facto standards include:

· Hayes command set for controlling modems

· Kermit Communications Protocol

· Xmodem Communications Protocol

· Hewlett-Packard Printer Control Language (PCL) for laser printers.

· PostScript page description language for laser printers

Dequantization
The process of rescaling quantized DCT coefficients after their representation in the bitstream has been decoded and before they are presented to the inverse DCT.

Digital videoA video represented by computer-readable binary numbers that describe a finite set of colors and luminance levels. See analog video.

DIAL UP ACCESS
Refers to connecting a device to a network via a modem and a public telephone network. Dial-up access is really just like a phone connection, except that the parties at the two ends are computer devices rather than people. Because dial-up access uses normal telephone lines, the quality of the connection is not always good and data rates are limited. In the past, the maximum data rate with dial-up access was 28.8 Kbps (28,800 bits per second), but new technologies such as ISDN are providing faster rates.

An alternative way to connect two computers is through a leased line, which is a permanent connection between two devices. Leased lines provide faster throughput and better quality connections, but they are also more expensive.

DIMM
Short for dual in-line memory module, a small circuit board that holds memory chips. A single in-line memory module (SIMM) has a 32-bit path to the memory chips whereas a DIMM has a 64-bit path. Because the Pentium processor requires a 64-bit path to memory, you need to install SIMMs two at a time. With DIMMs, you can install memory one DIMM at a time.

Disc
Flat, circular, rotating medium that can store various types of information, both analog and digital. "Disc" is often used in reference to optical storage media, while "disk" refers to magnetic storage media. Disc is often used as a short form for videodisc or compact audio disc (CD).

Disk
Alternative spelling for "disc" that generally refers to magnetic storage medium on which information can be accessed at random. Floppy disks and hard disks are examples.

Display order
The order in which decoded pictures are displayed. Normally this is the same order in which the pictures entered the encoder.

Dithering
A process that improves the perceived quality of a screen graphic when the color palette is reduced. For example, when converting from 24-bit color to 8-bit color (an 8-bit palette has only 256 colors compared to the 24-bit palette's millions), dithering adds pixels of different colors to simulate the original color. Dithering is also known as "error diffusion."

Double buffering
Double buffering is a technique of dividing the frame buffer into two areas, one "draw" buffer and one display buffer. This allows the application to display a frame of animation from one buffer while drawing the next frame into the other buffer, therefore increasing performance by doing two things at once.

DRAM
Pronounced dee-ram, DRAM stands for dynamic random access memory, a type of memory used in most personal. A type of physical memory used in most personal computers. The term dynamic indicates that the memory must be constantly refreshed else it will lose its contents.

DSVD
(Digital Simultaneous Voice and Data) An all-digital technology for concurrent voice and data (SVD) transmission over a single analog telephone line. DSVD is endorsed by Intel, Hayes, U.S. Robotics and others and has been submitted to the ITU for possible standardization. DSVD modems became available in the first half of 1995.

DTMF
Short for Dual Tone Multi-Frequency, the system used by touch-tone telephones. DTMF assigns a specific frequency, or tone, to each key so that it can easily be identified by a microprocessor.